Air preheater for furnaces



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Dec. 21,1926.

H. M. FERGUSON AIR PREHEATER Foa FuRuAcns origingl Filed Oct 1. 1923 A rroRNEY.

Patented Dec. 2l, 1926..

Unirse stares HUGH M. FERGUSON, OF

roam nunon, MICHIGAN.

Am `1 REHEATER non FURNACES.

Application filed October 1, .1923, Serial This invention relates to means for directing a wide jet or blast of very hot air into the zone of combustion just above the upper surface of the burning coal or other` fuel in the fire-pot or on the grate of a furnace in order to accelerate and complete thecombustion of the fuel, and its object is to provide a device of this character which can be attached to the fire-door of substantially every type of furnace at low cost.

This invention consists in a nozzle adapt'- ed to be attached'to the inside of the tire-door or other convenient part of a furnace and provided with projections such as fins on its outer surface to receive the radiant heat of the fire and with projections on its inner surface tov transmit this heat to the air passing through the nozzle to the fire.

It further consists of the details of construction illustrated .in the accompanying drawing and particularly pointed out in the claim. Y Y I In the drawing, Fig. l'. is an elevation of this improved air nozzlefattached to a firedoor, .the furnace being broken away Vto show the manner of mountingthe nozzle.

y Figs. 2, 3 and 4 are sections on the lines 2-2, 3 3 and 1-Lof Fig. l respectively. l

Similar reference charactersrefer to "like parts throughout the several views.

The .fires `of boilers and `otherfurnaces often smoke and are otherwiseinefiicient because .ofan insuflicientsupply of air, the

Vfuel being only partially consumed. This is particularly true in the hotV air furnaces .used for heating dwellings, which, lbecause of the unskilled attendance, arev peculiarly. liable to smoke. Y` I have found that this smoking can be practically prevented by di` recting a blast or current of air into the very' hot gases that rise from the bed of burning coal on. the grate of the furnace by means of a nozzle embodying the present invention.

In the drawing, the furnace l is shownV equipped with a fuel chute 2 closed by means fof a door 3 which'is hinged-in any p desired manner. The nozzle 4 is shown secured to this door by means of the screws passing through the fiange 6. The nozzle preferably inclines downwardly toward the' fuel 7 in the fire-pot and the flow of air through the nozzle may be regulated by a disk 8 mounted on ascrew 9. This Vdisk may be moved towardl and from the door to regulate the flow of air through Vthe openings i 10 in the door.

Ne. 665,778. Renewed November c, i926.

` I-prefertheupper Wall 12 land lower wall 13. of the nozzle to approach each other while the side walls lt separate toward theinner end of the nozzle so as to flatten the blast of air passing to the flameabove the'y Fins or ribs 16 are attached to the 0 fuel. upper and lower-walls and extend inwardly so asto divide the interior of the nozzle into narrow channels. -Transverse fins or ribs areattached ,tov the outer surface of furnace, it will be highly heated bythe finsy 16, and as it isv directed directly into the `zoneof combustion above thev fuel on the grates, it will Vmingle with the lburning gases 'y and cause more intense andfcoinplete combustion of the fuel. By forming the discharge end ofthe 4nozzle quite wide, thel `blast of hot air may be Vspread out to the width of the fuel lon the grate. Y I have found that -the transverse Yarrangement of the-external fins or ribs is veryyeffective for intercepting vand absorbing the heat radiated by the burning fuel for the purpose of i obtaining'the `heat-necessaryV to bring 'the vincoiningair to-a high-temperature, whichv "results in the `complete combustion of the, i

gasitied fuel y It should berunderstood that the nozzle 'may be attachedto Aany other convenient part ofy the furnace. l

The details Vand proportions of the various parts of this nozzle be changedv A i by those skilled in the art to adapt it to the different types Vvand sizes of furnaces, without departing from the spirit of myL invention as set forth inthe following claim. I claim i ber, a' nozzle extending downwardlyfrom an apertured portion of the furnace toward the zone of combustion, said'nozzle having longitudinal interior ribs and transverse In a furnace having a combustion chamexternal ribs extendingy around the nozzle, Y

vthe top and bottom of the nozzle approaching and thesides separating toward the discharge end soV as to ydeliver a wide blast` ofair to the zon-e of combustion.

HUGH M. ,'.Fnneuson 

